Inspection of limited access areas within enclosures, such as aircraft structures, may require disassembly and reassembly of the structure, which is costly and time consuming. As an alternative, such enclosed areas may include an access opening sized to receive a sensor or other instrument that enables a visual inspection. If the interior to be inspected is relatively open, use of such a sensor may be effective. However, in many applications, such an enclosure may include an obstructed interior that may include hardware or other structure that makes access and inspection difficult.
For example, certain internal aircraft structures may require in-service inspection, but such structures may be obstructed by tubes, brackets and actuators that must be removed first. In some cases, initial inspections may take more than 1000 hours, and subsequent inspections may take more than 500 hours. Other internal aircraft components may be obstructed by other structural elements. Because of structural removal issues, an initial aircraft inspection may take more than 2000 hours, and recurring inspections as much as 1100 hours.
Currently, such inspections may be performed using borescopes and remote cameras shaped to be inserted into limited access areas. Such devices may be able to see surface flaws or damage, but not subsurface damage. In many cases, features found using these devices and methods may be misdiagnosed as damage, and only determined to be benign markings after costly disassembly. Fatigue inspections of titanium attach fittings on aircraft may be programmed as visual borescope inspections, but if crack-like indications are found, there is no current method of confirming them other than simply disassembly of the empennage.
Further, with the increase in use of bonded and co-cured composite structures for aircraft, access to the interior for production and in-service inspection may be very difficult, costly, and time-consuming. Such inspection may be so expensive that certain lower-cost structure designs cannot be utilized because of the high cost of performing in-service inspections.
Accordingly, there is a need for a system and method for nondestructive inspection in limited, enclosed areas. There is also a need for a system and method for nondestructive testing that tracks the position and orientation of an inspection device in a confined space.